A major puzzle in biology is the origin of novel phenotypes. Innovative phenotypes are important to understanding medically important phenomena such as host-parasite interactions and the development of antibiotic resistance in pathogens. Classic models hold that mutational processes generate new phenotypes through gene duplication, domain shuffling, and other mechanisms that modify existing genes rather than making new ones. Random sequences may be prone to toxic aggregation rather than folding to a functional state: this is a major reason why tinkering mechanisms have been posited. However, recent discoveries, including our own, show that new genes can evolve de novo from non-coding sequences and that new portions of genes can also arise in this manner. The aims of this proposal are: 1) to identify more such cases, 2) to investigate the roles of ordered structure and intrinsic structural disorder in de novo protein-coding innovation, and 3) to examine the structural properties of proteins, or portions of proteins, encoded by new coding sequence. Significant possible outcomes include 1) insights into selection processes that allow new genes to arise, 2) the discovery of novel proteins and an ability to compare their properties to those of highly evolved proteins, yielding insights into the protein folding code and protein design/engineering. The newness of this research area, as well as the incorporation of cutting-edge evolutionary theory and studies of de novo protein structure, make this work highly innovative. The PI team is interdisciplinary and complementary, including both an evolutionary biologist and an experimental structural biologist/biochemist.